/*
 * Copyright (C) 2018 Donlon.
 *
 * 2018秋季C语言练习题（5）
 * http://10.105.242.83/contest/507/
 *
 * A. 危险的民主
 */

#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>
#include <string.h>

void bubble_sort(int arr[], int n) {
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < i; ++j) {
      if (arr[j] > arr[i]) {
        arr[i] = arr[i] ^ arr[j];
        arr[j] = arr[i] ^ arr[j];
        arr[i] = arr[i] ^ arr[j];
      }
    }
  }
}

int main() {
  int k;
  scanf("%d", &k);
  int data[200] = {0};

  for (int i=0; i < k; i++) {
    scanf("%d", data + i);
  }

  bubble_sort(data, k);

  int sum = 0;
  for (int i = 0; i <= k/2; i++) {
      sum+= data[i]/2+1;
  }

  printf("%d", sum);
}
